Hyaluronic acid presents widely in living tissues such as cockscombs, umbilical cords, skin, cartilages, vitreous bodies, joint fluid, and is widely used as a component of cosmetics, pharmaceuticals, and foods, for example.
Laid-open Patent Application No. JP 06-25306 describes solvent-insolubilized hyaluronic acid binding to a fatty acid residue to an alcoholic hydroxyl group. However, the solvent-insolubilized hyaluronic acid described in JP 06-25306 has low solubility in both water and ethanol, and thus is not suitable for blending with products containing water or ethanol (e.g., cosmetics, pharmaceuticals, and foods).